Liquid crystal material is widely used in a number of fields with the development of liquid crystal technology.
For example, a conventional optical lens set always includes at least two lenses which are moved cooperatively to achieve an effect of changing focus. During an actual application, such optical lens set usually is massive and has a big bulk, and accordingly brings inconvenience to the user.
A liquid crystal lens is an optic assembly which focuses or diverges light utilizing a birefringent characteristic of liquid crystal molecules and a characteristic of changing arrangement of the liquid crystal molecules with electric-field distribution. The liquid crystal lens can change aligning directions of the liquid crystal molecules via changing an operating voltage, so as to achieve an effect of changing focus. Furthermore, a lightweight and thin characteristic is a big advantage of the liquid crystal lens, so that the liquid crystal lens can obtain an effective effect of changing focus in a limited space.
In prior art, in order to achieve a desired effect of phase retardation, the liquid crystal lens generally needs a thick liquid crystal layer. However, the overly-thick liquid crystal layer may cause a response time of the liquid crystal lens to be excessively long. For example, if the liquid crystal layer has a thickness of 60 μm, the response time thereof would be about 30 seconds and the operating voltage thereof needs to exceed 30 Volts. Although a focusing time of the liquid crystal lens may be improved by changing the operating voltage thereof in the prior art, it is only limited to changing the focusing time of the liquid crystal lens. That is to say, the time spent for the liquid crystal molecules in the liquid crystal lens to revert to an initial aligning direction still is overly long and is not improved. Therefore, it is inconvenient for the user during usage.
Accordingly, one of development directions for liquid crystal technology is how to reduce the response time of the liquid crystal lens, and particularly is to shorten the time spent for the liquid crystal molecules to revert to the initial aligning direction so as to enhance the efficiency of the liquid crystal lens.